JP7453659B2 - Radiant light detection device - Google Patents

Description

The present invention relates to a radiation light detection device.

All objects emit light (electromagnetic waves) through thermal radiation, and as known from Planck's law, the wavelength components (spectrum) of the emitted light are determined by the temperature of the object. For example, an object at room temperature emits mid-infrared light with a peak wavelength of around 10 μm. Infrared thermography is a device that detects light emitted from an object due to thermal radiation (also referred to as radiant light) using a microbolometer and displays it as a thermal distribution image.

Japanese Patent Application Publication No. 06-94537

Radiant light from an object and radiation light from a casing in which the microbolometer is housed and various parts within the casing (hereinafter referred to as "casing etc.") enter the microbolometer. Therefore, in general infrared thermography, a shutter is installed in front of the microbolometer inside the housing, and with the shutter closed, the amount of light received by the microbolometer is measured and stored as the amount of radiant light from the housing, etc. ing. Then, the amount of radiant light from the object is determined by subtracting the amount of radiant light from the casing or the like from the amount of light measured with the shutter open (Patent Document 1). However, if a shutter is provided inside the housing or a shutter opening/closing mechanism is installed inside or outside the housing, the device becomes larger.

Further, the amount of radiation from an object that the microbolometer receives is determined by the temperature of the object to the fourth power and the temperature of the microbolometer to the fourth power. That is, the radiation light emitted from the object propagates from the object to the microbolometer according to the difference (gradient) between the temperature of the object to the fourth power and the temperature of the microbolometer to the fourth power.

Therefore, even when measuring the amount of radiant light from the same object, if the temperature of the thermography housing or the microbolometer changes due to changes in the outside temperature, the amount of radiant light received by the microbolometer will change.

The problem to be solved by the present invention is to provide a radiation light detection device in which the influence of outside temperature is suppressed to a small extent without increasing the size of the device.

The radiation light detection device according to the present invention, which has been made to solve the above problems, includes:
a casing having a window;
a radiant light detector arranged in the housing that detects radiant light from the measurement target that enters through the window;
It is characterized by comprising a temperature control member for adjusting an optical path of radiation light from the window portion to the radiation light detector to a predetermined temperature.

In the radiation light detection device having the above configuration, the radiation light from the measurement target that enters through the window is detected by the radiation light detector. At this time, regardless of changes in the outside temperature, the optical path of the radiant light from the window to the radiant light detector is adjusted to a predetermined temperature by the temperature control means, so the measurement results of the radiant light from the object to be measured are The influence of outside temperature can be suppressed to a small level.

In the radiation light detection device configured as described above, preferably, the temperature control means includes a thermally conductive sheet provided within the housing so as to surround the optical path.
According to the above configuration, the heat generated within the optical path is dissipated through the thermally conductive sheet, so that the temperature inside the optical path can be adjusted to a low temperature. Further, since the thermally conductive sheet is provided so as to surround the optical path, the temperature of the entire optical path can be maintained substantially constant. Examples of the thermally conductive sheet include graphite sheets.

In the above configuration, it is preferable that the thermally conductive sheet has a contact portion that comes into contact with the radiation light detector or the object to be measured.

In the radiation light detection device described above, the heat of the radiation light detector or the heat of the object to be measured is conducted to the thermally conductive sheet through the contact portion. Therefore, the temperature within the optical path can be adjusted to approximately the same temperature as the radiation light detector or the measurement target. In particular, a configuration in which the thermally conductive sheet includes a contact portion that comes into contact with the object to be measured is useful when the temperature of the radiation light detection device is higher than the temperature of the object to be measured. In such a case, first, the contact portion is brought into contact with the object to be measured to bring the temperature in the optical path close to the temperature of the object to be measured. In this way, by bringing the temperature in the optical path closer to the temperature of the object to be measured, the temperature in the optical path can be lowered than that of the object to be measured in a relatively short period of time, thereby shortening the time it takes to start measuring radiant heat. Can be done. Methods of lowering the temperature in the optical path than the object to be measured include, for example, bringing the contact part of a thermally conductive sheet into contact with an object that is lower in temperature than the object to be measured, or using a cooling device to cool the housing or detect radiation light. One example is to cool the container.

Therefore, in the above radiation light detection device,
Preferably, the temperature control means includes a cooling means for cooling at least one of the casing and the radiation light detector.

In the above configuration, preferably the temperature control means includes an in-light path temperature detector for detecting the temperature in the light path, an in-light path temperature setting unit for setting the temperature in the light path, and an in-light path temperature setting unit. and a control section that controls the cooling means so that the temperature reaches a temperature set by the cooling section.

According to the above configuration, the temperature within the optical path can be adjusted to an arbitrary temperature set by the optical path internal temperature setting section.

Further, the radiation light detection device described above may further include a heating means for heating the object to be measured.

In the above configuration, by heating the measurement object, the temperature within the optical path becomes relatively low, and the amount of radiation light propagating from the measurement object into the optical path can be increased.

In the above configuration, the heating means may include an ultrasonic vibrator provided within the housing so as to surround the window. In this case, the heating means may further include an ultrasonic vibration setting section that sets the frequency and/or amplitude of the ultrasonic vibrations emitted by the ultrasonic vibrator.

According to the above configuration, the object to be measured can be ultrasonically heated by applying the ultrasonic vibrations generated by the ultrasonic transducer to the object to be measured. In this case, standing waves may be formed within the measurement object depending on the frequency and/or amplitude values of the ultrasonic vibrations applied to the measurement object. In a standing wave, energy is concentrated at the nodes, so the nodes are heated more strongly than other parts. Therefore, when a standing wave of ultrasonic vibration is formed with a node located near the measurement point, the light (radiation light (infrared)) emitted from the measurement point becomes stronger than the light emitted from other locations. . In order to form a standing wave of ultrasonic vibration with a node located near the measurement point, the frequency and/or The amplitude needs to be adjusted. In a configuration in which the heating means includes an ultrasonic vibration setting section, the frequency and/or amplitude of the ultrasonic vibrations emitted by the ultrasonic vibrator can be set to appropriate values.

In the configuration including the heating means, further:
an object temperature detector that detects the temperature of the measurement object;
an object temperature setting unit for setting the temperature of the measurement object;
It is preferable to include a control section that controls the heating means so that the temperature reaches the temperature set by the object temperature setting section.

According to the above configuration, the temperature of the object to be measured can be adjusted to an arbitrary width temperature set by the object temperature setting section.

Furthermore, in the above radiation light detection device,
The radiation light detector has a light receiving surface and is configured to detect the intensity distribution of light on the light receiving surface,
a collimating unit disposed on the optical path between the window and the radiation light detector, which converts the radiation light from the object to be measured into a parallel beam, and divides the parallel beam into a first beam and a second beam; a phase shifter that emits light while imparting an optical path length difference between the first light beam and the second light beam; a light receiving surface of the radiation light detector such that the first light beam and the second light beam overlap each other at least in part; an interference optical system that makes the light incident on the
a processing unit that obtains an interferogram of the measurement point based on the light intensity distribution of the light receiving surface in a portion where the first light beam and the second light beam overlap, and obtains a spectrum by Fourier transforming the interferogram; It is good to have and .

According to the above configuration, it is possible to measure the spectral characteristics of the radiation light emitted from the object to be measured.

According to the present invention, the influence of outside temperature can be suppressed without increasing the size of the radiation light detection device.

1 is a top view (a) and a side view (b) showing a first example of a spectrometer that is an embodiment of the present invention. FIG. 2 is a perspective view showing a spectrometer with some parts omitted. Top view (a), side view (b), and view from the reflective surface side (c) of the phase shifter. An explanatory diagram of the operation of the spectrometer. FIG. 7 is a side view of a modified spectrometer. FIG. 2 is a schematic configuration diagram showing a second example of a spectrometer that is an embodiment of the present invention. Figures (a) to (d) showing the configuration of the transmission type optical element, and Figure (e) showing how light passing through the transmission type optical element is incident on the light receiving surface of the detector. FIG. 3 is a schematic configuration diagram showing a third example of a spectrometer that is an embodiment of the present invention. FIG. 4 is a schematic configuration diagram showing a fourth example of a spectrometer that is an embodiment of the present invention. FIG. 3 is a schematic configuration diagram showing a fifth example of a spectroscopic measurement unit that is an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The radiation light detection device according to the present invention will be described below with reference to specific examples.

[Example 1]
DESCRIPTION OF THE PREFERRED EMBODIMENTS A first example of a spectrometer, which is an embodiment of a radiation light detection apparatus according to the present invention, will be described with reference to the drawings.
1 and 2 show the overall configuration of a spectrometer 1 of this embodiment. Note that in FIGS. 1A and 2, a part of the casing is omitted so that the internal structure of the spectrometer can be seen.

[Configuration of spectrometer]
The spectrometer 100 includes a casing 10, a phase shifter 20 housed inside the casing 10, an objective lens 31, an imaging lens 32, and a detector 40 as a radiation light detector. The casing 10 includes two rectangular box-shaped casings 101 and 102, one large and one small. Hereinafter, the larger one will be referred to as the first housing 101, and the smaller one will be referred to as the second housing 102. The phase shifter 20, objective lens 31, and imaging lens 32 are housed in a first housing 101, and the detector 40 is housed in a second housing 102, respectively.

The first housing 101 is composed of a rectangular plate-shaped base plate 11, four side walls 12 to 15, and a lid 16. The side wall portions 12 to 15 are removably connected to each other, the side wall portions 12 to 15 and the base plate 11, and the side wall portions 12 to 15 and the lid 16 are each removably connected by screws (not shown).

The objective lens 31 is arranged on the base plate 11 so that its lens surface is parallel to the side wall portion 12. Further, the imaging lens 32 is arranged on the base plate 11 so that its lens surface is parallel to the side wall portion 13. The objective lens 31 and the imaging lens 32 are held between the base plate 11 and a lens holder 33 erected on the upper surface of the base plate 11 . The lens holder 33 is made up of an L-shaped member when viewed from above and a pair of legs, and the lower ends of the pair of legs are fixed to the upper surface of the base plate 11. Recesses are formed on the upper surface of the base plate 11 at appropriate locations corresponding to the positions of the phase shifter 20, objective lens 31, imaging lens 32, and lens holder 33. A recess is formed into which the lower end of the leg is inserted. The objective lens 31 and the imaging lens 32 are positioned by inserting the lower end of the objective lens 31, the lower end of the imaging lens 32, and the lower end of the leg of the lens holder 33 into these recesses. By holding both the objective lens 31 and the imaging lens 32 with one lens holder 33, the objective lens 31 and the imaging lens 32 can be brought close to each other.

An inlet 70 (corresponding to the window of the present invention) for introducing radiation light from the object to be measured into the housing 10 is provided at a portion of the side wall 12 that faces the objective lens 31 . The introduction port 70 is located between a cylindrical portion 71 projecting outward from the side wall portion 12, a condensing lens 72 fitted into the cylindrical portion 71, and between the condensing lens 72 and the objective lens 31. It has a conjugate plane grating 73 arranged on the conjugate plane of the objective lens 31. The conjugate plane grating 73 is held in a grating holder 74 erected on the upper surface of the base plate 11 .

An exit port 80 for the radiant light (reflected light) that has passed through the imaging lens 32 is provided at a portion of the side wall portion 13 that faces the imaging lens 32, and the portion of the side wall where the exit port 80 is formed A second housing 102 is attached to the outer surface of the portion 13. Inside the second housing 102 , the detector 40 is arranged such that its light-receiving surface faces the outlet 80 and the light-receiving surface is located on the image-forming surface of the imaging lens 32 . The detector 40 is composed of a two-dimensional array sensor having a plurality of light-receiving elements two-dimensionally arranged on a light-receiving surface.

The phase shifter 20 includes a fixed reflective member 21, a movable reflective member 22, and a drive mechanism 23 that drives the movable reflective member 22. The fixed reflective member 21 is made of a cubic metal block, and one surface of the fixed reflective member 21 is mirror-finished to form a reflective surface 21a (hereinafter also referred to as fixed reflective surface 21a). The fixed reflecting member 21 is fixed to the upper surface of the base plate 11 so that its reflecting surface 21a is inclined at 45 degrees with respect to the optical axes of the objective lens 31 and the imaging lens 32.

A drive mechanism 23 is fixed to the upper surface 21c of the fixed reflective member 21. The drive mechanism 23 is composed of, for example, an impact drive actuator, and moves a movable body 24 disposed above the drive mechanism 23 in the horizontal direction. The movable body 24 is a member having an L-shaped cross section and has a mounting plate part 24a and a mounting end part 24b bent downward from the end thereof, and is attached to the upper part of the drive mechanism 23 by the mounting plate part 24a. There is. The drive mechanism 23 is fixed to the mounting surface 21c of the fixed reflective member 21 so that the moving direction of the movable body 24 coincides with the normal direction of the fixed reflective surface 21a.

The movable reflecting member 22 is fixed to the mounting end 24b of the movable body 24. The movable reflective member 22 is made of a cubic metal block, and has a reflective surface 22a (hereinafter also referred to as movable reflective surface 22a) formed by mirror-finishing one surface, and a surface opposite to the reflective surface 22a (back surface). A fitting recess 22b is formed, and the fitting recess 22b is fitted into the attachment end 24b. The reflective surface 22a of the movable reflective member 22 has approximately the same size as the reflective surface 21a of the fixed reflective member 21.

As shown in FIG. 1(a), temperature control means are provided on the inner surface of the side wall of the first casing 101, the inner surface of the lid 16, and the inner surface of the second casing 102 (bottom plate, side wall, and top plate). A graphite sheet 90, which is a thermally conductive sheet, is attached to each. Note that in FIG. 2, illustration of the graphite sheet 90 is omitted.

Graphite Sheet 90 is known to have better thermal conductivity than copper and aluminum, which have high thermal conductivity among metals, and has been used by Kaneka Corporation (product name: ^GraffinitiTM ) and Panasonic Corporation (product name : PGS Graphite Sheet) etc. In this embodiment, these commonly sold graphite sheets can be purchased and used.

Furthermore, two Peltier elements 95 and 96 are attached to the lower surface of the housing 10. One Peltier element 95 is attached to the lower surface of the first housing 101, and the other Peltier element 96 is attached to the first housing 101 and the lower surface of the second housing 102 so that most of the Peltier element 96 is located on the lower surface of the second housing 102. It is attached across the lower surface of the two housings 102. The Peltier elements 95 and 96 are both in contact with the lower surface of the housing 10 on their heat absorption sides (cooling sides). The Peltier elements 95 and 96 correspond to the cooling means of the present invention.

A control device 50 that controls the detector 40 and the Peltier elements 95 and 96 is housed inside the first housing 101 . Although detailed explanation and illustration are omitted, the control device 50 obtains an interferogram from the detection signal of the detector 40, and mathematically performs Fourier transform on this interferogram to obtain the relative intensity of each wavelength of the radiation light. It is equipped with a calculation unit that calculates spectral characteristics (spectrum), a processing unit that converts the calculation results of the calculation unit into an image, and a display or printer that outputs the processing results of the processing unit.

[Measurement of spectral characteristics of radiant light]
The operation of measuring the spectral characteristics of the radiation light emitted from the object to be measured using the spectrometer 100 having the above configuration will be described with reference to FIG. 4. The method for measuring spectral characteristics using the spectrometer 100 is called imaging two-dimensional Fourier spectroscopy.

First, before starting the measurement of the spectral characteristics of the radiation light of the measurement object S, current is supplied to the Peltier elements 95 and 96. As a result, the first housing 101 and the second housing 102 located on the heat absorption side of the Peltier elements 95 and 96 are cooled, and the graphite sheets attached to the inner surfaces of the first housing 101 and the second housing 102 are further cooled. Components placed in these casings 101 and 102 are cooled through 90. At this time, current is supplied to the Peltier elements 95 and 96 for a preset time so that the temperature of the spectrometer 100 is lower than the temperature of the object to be measured by a predetermined temperature.

Next, the drive mechanism 23 of the phase shifter 20 of the spectrometer 100 is driven to reciprocate the movable reflection member 22 in the direction shown by arrow A in FIG. More specifically, the movable reflective member 22 is moved between a reference position where the movable reflective surface 22a and the fixed reflective surface 21a are on the same plane and a variable position where the movable reflective surface 22a is behind the fixed reflective surface 21a. move back and forth at a constant speed. The driving of the drive mechanism 23 is controlled by a control device 50.

Subsequently, the spectrometer 100 is installed so that the inlet 70 of the spectrometer 100 faces the object S to be measured. As a result, the radiant light 110 emitted from the measurement object S due to thermal radiation enters the first housing 101 from the introduction port 70. The radiation light 110 that has entered the first housing 101 passes through the condenser lens 72 and the objective lens 31, and then becomes parallel light and reaches the phase shifter 20. The radiant light 110 that has reached the phase shifter 20 is incident on both the fixed reflecting surface 21a and the movable reflecting surface 22a so as to straddle both the reflecting surfaces, and is reflected by each reflecting surface.

The light reflected by the fixed reflective surface 21a (fixed reflected light) and the light reflected by the movable reflective surface 22a (movable reflected light) each pass through the imaging lens 32 and then exit from the outlet 80 to the second housing 102. is incident on the light receiving surface of the detector 40, and is focused on the light receiving surface of the detector 40 to form interference light. A plurality of light receiving elements are arranged on the light receiving surface of the detector 40, and each light receiving element generates a detection signal according to the intensity of the interference light of the radiation light 110 emitted from the object S to be measured. The detection signal of each light receiving element is output from the detector 40 to the control device 50 and processed.

By moving the movable reflective surface 22a and changing the optical path length difference between the fixed reflected light and the movable reflected light, the intensity of the interference light changes. Since the measurement object S emits radiation light 110 in a predetermined wavelength range according to its temperature, the detection signal from the detector 40 is processed in the control device 50 to indicate a change in the intensity of the interference light. An interferogram is acquired, and the spectral characteristics (spectrum) of the radiation light 110 are acquired by mathematically Fourier transforming this interferogram. In the spectrometer 100 according to the present embodiment, since a plurality of light receiving elements are two-dimensionally arranged on the light-receiving surface of the detector 40, it is possible to two-dimensionally measure the spectral characteristics of the radiation light 110 emitted from the measurement object S. Can be done.

Further, in this embodiment, Peltier elements 95 and 96 are provided for cooling the casing 10, and a graphite sheet 90 is provided inside the casing 10, so that the radiant light 110 incident on the casing 10 reaches the detector 40. A graphite sheet 90 surrounds the optical path of the graphite sheet 90. Then, the spectral characteristics of the radiant light 110 from the measurement object S are measured in a state where the temperature inside the housing 10 is lower than the temperature of the measurement object S. Therefore, the radiation light 110 from the measurement target S can be stably measured regardless of the outside temperature.

In particular, in this embodiment, a graphite sheet 90 is provided inside the housing 10 so that the graphite sheet 90 surrounds the optical path of the incident radiation light 110 from the housing 10 to the detector 40. Therefore, the entire optical path of the radiation light 110 entering the housing 10 up to the detector 40 can be efficiently and uniformly cooled.

According to experiments conducted by the inventor of the present application, when the casing 10 is cooled by the Peltier elements 95 and 96 without the graphite sheet 90, it is difficult to uniformly cool the temperature of the components inside the casing 10, or Although it took some time for the temperature to become uniform, by providing the graphite sheet 90, it was possible to uniformly cool the temperature of the components inside the casing 10 in a short time.

In this embodiment, a temperature sensor may be provided to detect the temperature inside the housing 10, and the Peltier elements 95 and 96 may be operated based on the result of the temperature sensor. Further, a temperature sensor that detects the temperature inside the casing 100 and an outside temperature sensor that detects the outside temperature may be provided, and the Peltier elements 95 and 96 may be operated based on the detection results of the temperature sensor and the outside temperature sensor. Furthermore, a humidity sensor may be provided in addition to the temperature sensor and the outside air temperature sensor to cool the casing 10 to a temperature that does not cause dew condensation on the casing 10 and the components within the casing 10. Furthermore, a temperature sensor for detecting the temperature inside the casing 10 and a temperature setting section for setting the temperature of the casing 10 are provided, and a Peltier element 95 is installed so that the temperature reaches the temperature set by the temperature setting section. 96 may be operated. According to these configurations, the spectral characteristics of the radiant heat from the measurement object S can be measured accurately and accurately.

Alternatively, as shown in FIG. 5, a heat sink 97 may be disposed below the Peltier elements 95 and 96 (on the heat radiation side), and a fan 98 may be disposed below the heat sink 97. According to this configuration, the housing 10 can be cooled in a shorter time. In the above configuration, the cooling means is composed of the Peltier elements 95 and 96, the heat sink 97, and the fan 98.

[Example 2]
FIG. 6 shows a second example of a spectrometer that is an embodiment of the present invention.
[Configuration of spectrometer]
This spectrometer 200 includes a cylindrical casing 201, a transmission type optical element 210 and a detector 220 (corresponding to a radiation light detector) housed inside the cylindrical casing 201, and an ultrasonic heating device 250.

A circular window 202 is provided at one end of the housing 201 for introducing radiation light from the measurement object S into the housing 201. A window material made of a material with excellent mid-infrared light transmittance is fitted into the window portion 202. Furthermore, a heat insulating sheet 290 is attached to the inner peripheral surface of the housing 201 as a temperature control means.

The detector 220 is arranged inside the other end of the housing 201 so that its light receiving surface 221 faces the window 202 . The detector 220 is composed of a two-dimensional area sensor such as an infrared CCD camera in which a plurality of pixels are two-dimensionally arranged. The detector 220 is connected to the processing device 230 via a signal line, and outputs a detection signal to the processing device 230.

The transmission type optical element 210 has a light entrance surface 211 and a light exit surface 212 on the back side thereof, with the light entrance surface 211 facing the window portion 202 side and the light exit surface 212 facing the light receiving surface 221 side of the detector 220. It is arranged between the window part 202 and the detector 220, as shown in FIG.

7(a) is a view of the transmission type optical element 210 viewed from the light exit surface 12 side, FIG. 7(b) is a sectional view taken along line bb' in FIG. 7(a), and FIG. 7(c) Figure 7(d) is a cross-section taken along line cc' in Figure 7(a) viewed from the top of the page, and Figure 7(d) is a cross-section taken along line dd' in Figure 7(a) viewed from the bottom of the page. The view shown in FIG. 7E is a diagram showing how light emitted from the light emitting surface 212 of the transmissive optical element 210 enters the light receiving surface 221 of the detector 220. Here, the top, bottom, left and right in FIG. 7A are the top, bottom, left and right of the transmission type optical element 10.

The transmission type optical element 210 consists of an optical element that is circular when viewed from the light entrance surface 211 side (or the light exit surface 212 side), and the light entrance surface 211 is configured in a substantially spherical shape that is convex outward. . On the other hand, the light emitting surface 212 is composed of a planar first light emitting surface 212A and a second light emitting surface 212B arranged side by side. It is inclined downward and upward toward the light entrance surface 211 side.

Further, the first light emitting surface 212A is not inclined in the cc' direction (that is, the left-right direction) in FIG. 7(a), whereas the second light emitting surface 212B is It is tilted at a predetermined angle toward the light entrance surface 211 from c to c'. That is, the second light exit surface 212B is inclined upward from the center line CL toward the light entrance surface 211, and is also tilted from the right side toward the left toward the light entrance surface 211 side. Therefore, the first light exit surface 212A and the second light exit surface 212B are not symmetrical with respect to the center line CL.

The ultrasonic heating device 250 includes an ultrasonic transducer 251 disposed within a housing 201, a plate member 252 as a reflection plate provided outside the housing 201, and a drive device 253 that drives the ultrasonic vibrator 251. It is equipped with The ultrasonic transducer 251 has an annular shape and is fixed to the inner surface of the housing 201 so as to surround the window portion 202. The plate material 252 faces the ultrasonic transducer 251 with a predetermined distance therebetween.

[How to use the spectrometer]
A method of using the above spectrometer 200 will be explained. Here, the object to be measured S is an object with a small thickness such as an earlobe.
First, the casing 201 and the plate material 252 of the spectrometer 200 are placed on both sides of the measurement target S with the measurement target S in between. Then, the window portion 202 and the plate material 252 are respectively brought into contact with the surface of the object S to be measured.

In this state, when the drive device 253 is operated to supply AC power to the ultrasonic transducer 251, ultrasonic vibrations are generated in the area (measurement area) between the plate 252 and the window 202 of the object S to be measured. , the measurement area is ultrasonically heated. As a result, infrared rays (radiant light) are emitted from the measurement area, and the infrared rays enter the light entrance surface 211 of the transmission type optical element 210 in the housing 201 through the window portion 202. Among the infrared rays incident on the transmission optical element 210, the infrared rays emitted from the measurement point SP, which is the focal point of the transmission optical element 210, become a parallel light flux and head toward the light output surface 212, and are It is divided into a first beam and a second beam and is emitted. The first light beam and the second light beam emitted from the light output surface 212 enter the light receiving surface 221 of the detector 220 in a state where they partially overlap, forming an interference image of the first light beam and the second light beam. That is, in the transmission type optical element 210, the light entrance surface 211 functions as a collimating beam forming section, and the light exit surface 212 functions as a phase shifter and an interference optical system. Therefore, by measuring the light intensity distribution of the interference image with the detector 220, an interferogram of infrared rays emitted from the measurement point SP is obtained, and by Fourier transforming this interferogram with the processing device 230, the measurement point Spectral characteristics of SP can be obtained.

In this manner, in this embodiment, the object to be measured is heated by the ultrasonic heating device 250, so that a temperature difference can be created between the object to be measured and the casing. Further, since the heat insulating sheet 290 is attached to the inner surface of the casing 201, the temperature inside the casing 201 can be kept uniform and lower than the outside temperature. Therefore, the radiation light from the measurement target S can be stably measured regardless of the outside temperature.

[Example 3]
FIG. 8 shows a third example of a spectrometer that is an embodiment of the present invention. This spectrometer 200A includes a vibration adjustment unit 255 that adjusts the frequency of AC power supplied to the ultrasonic vibrator 251 by the drive device 253 of the ultrasonic heating device 250 and the amplitude of the ultrasonic vibration generated by the ultrasonic vibrator 251. This embodiment differs from the second embodiment in that it includes an operating section 256 that is operated by the user. The vibration adjustment section 255 and the operation section 256 correspond to the ultrasonic vibration setting section of the present invention.

Further, the spectrometer 200A includes a mounting member 260 for mounting the spectrometer 200 (casing 201) and the plate material 252 on the measurement target S. The mounting member 260 is made of, for example, a clip, and the plate material 252 and the casing 201 are respectively attached to both ends of the clip.

When the measurement target S is held between the mounting members 260, the plate 252 and the casing 201 are fixed to the measurement target S such that the plate 252 and the window material 202 face each other with the measurement target S in between. The configuration of the spectrometer 200A other than those described above is the same as the spectrometer 200 of the second embodiment, so the same parts are given the same reference numerals and the explanation thereof will be omitted.

A method of using the spectrometer 200A will be explained. Here, the object to be measured S is also an object with a small thickness such as an earlobe.
First, the object to be measured S is sandwiched between the mounting members 260, and the housing 201 and the plate material 252 are fixed to both sides of the object to be measured.

In this state, when the drive device 253 is operated to supply AC power to the ultrasonic transducer 251, ultrasonic vibrations are generated in the measurement area between the plate material 252 and the window part 202 of the object to be measured S, and the measurement area is is heated by ultrasonic waves. At this time, operate the operation unit 256 to appropriately adjust the frequency of the AC power supplied to the ultrasonic transducer 251 and the amplitude of the ultrasonic vibration generated by the ultrasonic transducer 251, A standing wave with nodes located at is formed in the measurement area.

FIG. 8 schematically shows how a standing wave Sw is formed inside the measurement object S. In the standing wave Sw, energy is concentrated at the nodes, so the nodes are heated more strongly than other parts and emit high-energy infrared rays. High-energy infrared rays emitted from the measurement point SP enter the transmission type optical element 210 in the housing 201 through the window 202. The infrared rays from the measurement point SP that have entered the transmission type optical element 210 become a parallel light beam and head toward the light output surface 212, and are emitted from the light output surface 212 after being divided into a first light beam and a second light beam. The first light beam and the second light beam emitted from the light emitting surface 212 enter the light receiving surface 221 of the detector 220 in a state where they partially overlap, forming an interference image of the first light beam and the second light beam. Therefore, by measuring the light intensity distribution of the interference image with the detector 220, an interferogram of the measurement point SP can be obtained, and by Fourier transforming this interferogram with the processing device 230, the spectral characteristics of the measurement point SP can be obtained. can be obtained.

Further, in this embodiment, it is possible to form a standing wave Sw of ultrasonic vibration located at the measurement point SP, and to generate high-energy infrared rays from the measurement point SP. Therefore, the infrared rays emitted from locations other than the measurement point SP, which do not contribute to the formation of an interference image on the light receiving surface 221 of the detector 220, can be suppressed to a small level, so that the S/N ratio can be increased.

In this embodiment and the second embodiment, the heat insulating sheet 290 is attached to the inner surface of the housing 201, but a thermally conductive sheet (graphite sheet) may be attached instead. When a graphite sheet is attached, the heat within the optical path can be released to the housing 201 side to cool the inside of the optical path.

[Example 4]
The spectrometer 300 shown in FIG. 9 includes a cylindrical housing 301, a phase shifter 320 housed in the housing 301, an objective lens 331, an imaging lens 332, a detector 340, and a Peltier element 395. ing. In this embodiment, the objective lens 331, phase shifter 320, imaging lens 332, detector 340, and Peltier element 395 are arranged in a line in this order from one end of the housing 301 to the other end. There is.

One end of the casing 301 has a shape cut along a plane that is inclined with respect to the central axis of the casing 301, and that part is made of a material that is highly transparent to infrared light. A window portion 302 is fitted. Further, a lid 303 is attached to the other end of the housing 301, and a Peltier element 395 is attached to the inner surface of the lid 303. The Peltier element 395 has its heat absorption (cooling) side in contact with the detector 340 and its heat generation side in contact with the lid 303. The lid 303 is made of a material with excellent thermal conductivity, and is configured to easily release heat generated on the heat generating side of the Peltier element 395 to the outside.

Further, a graphite sheet 390 is attached to the inner surface of the housing 301. A portion of the graphite sheet 390 extends from one end of the housing 301 (between the window 302 and the housing 301) to the outside of the housing 301, and is attached to the outer peripheral surface of one end of the housing 301. . A portion of the graphite sheet 390 attached to one end of the housing 301 will be referred to as a contact portion 391 below. Further, the other end side of the graphite sheet 390 is in contact with the detector 340. This contacting portion functions as a contact portion of the present invention.

The phase shifter 320 includes a first transmitting section 321 and a second transmitting section 322, which are semicircular transmission type optical members, and has an approximately disk-shaped configuration as a whole. The first transmission section 321 is made of an optical member with a constant thickness and whose incident surface and exit surface are parallel. On the other hand, the second transmission section 322 is made of a wedge-shaped optical member having an entrance surface that is inclined with respect to the entrance surface of the first transmission section 321 and an exit surface that is on the same plane as the exit surface of the first transmission section 3211. Become. In this embodiment, the thickness of the second transmitting section 322 gradually decreases from one side to the other, so that the incident surface is closer to the imaging lens 332 from one side to the other. is inclined to.

The imaging lens 332 consists of a plano-convex cylindrical lens. The imaging lens 332 has a surface on the phase shifter 320 side that is a cylindrical convex surface that projects toward the phase shifter 320, and a surface on the detector 340 side that is a plane parallel to the output surface of the phase shifter 320.

The detector 340 is composed of, for example, an infrared CCD camera in which a plurality of pixels are two-dimensionally arranged. Although not shown, a control device that controls the detector 340 and the Peltier element 395 is housed inside the housing 301. The control device includes an arithmetic unit and an arithmetic unit that obtains an interferogram from the detection signal of the detector 340, performs a Fourier transform on this interferogram mathematically, and obtains a spectral characteristic (spectrum) that is the relative intensity of each wavelength of radiation light. A storage section is provided for storing the calculation results of the section. An external terminal such as a personal computer can be connected to the spectrometer 300, and the calculation results stored in the storage section are imported into the external terminal, where they are converted into an image or output to a display, printer, etc. included in the external terminal. You can do it.

When measuring the spectral characteristics of the radiation light emitted from the object S to be measured using the spectrometer 300 configured as described above, one end of the housing 301 is brought into contact with the object S to be measured. As a result, the contact portion 391 comes into contact with the object to be measured S, and the heat of the object to be measured S is transferred to the graphite sheet 390. As a result, the temperature inside the housing 301 becomes approximately equal to the temperature of the measurement target S as time passes. In this state, the Peltier element 395 is operated for a predetermined period of time. Thereby, the detector 340 is cooled and becomes lower temperature than the measurement target object S. In this embodiment, in order to cool the detector 340 after making the temperature inside the casing 301 and the temperature of the measurement target S almost equal, the Peltier element 395 is operated for a preset time to cool down the measurement target S. The temperature difference between S and the detector 340 can be made almost constant. Furthermore, since the other end of the graphite sheet 390 is in contact with the detector 340, the entire interior of the casing 301 can be kept at approximately the same temperature as the detector 340.

On the other hand, radiant light emitted from the measurement object S enters into the housing 301 through the window material 302. After passing through the objective lens 331, the light enters the phase shifter 320, where the light is split into two, and enters the imaging lens 332 as a first measurement light and a second measurement light. The first measurement light and the second measurement light incident on the imaging lens 332 are focused on the light receiving surface of the detector 340 to form interference light. Since a large number of pixels are arranged on the light receiving surface, the intensity of the interference light is detected by these pixels. After the inside of the casing 301 has been cooled to a predetermined temperature, the control device takes in the detection signal from the detector 340 and performs predetermined arithmetic processing. As a result, an interferogram of the measurement object S is obtained, and a spectrum (spectral characteristics) is obtained by Fourier transforming this interferogram.

[Example 5]
FIG. 10 is a schematic diagram of a spectroscopic measurement unit according to a fifth embodiment of the present invention. This spectrometer unit includes a spectrometer 300A and a storage device 400. The spectrometer 300A differs from the spectrometer 300 of the fourth embodiment in that it does not include the Peltier element 395. Further, the graphite sheet 390 is attached only to the inside of the casing 301 and does not extend to the outside of the casing 301. Since the other configurations are almost the same as the spectrometer 300 of the fourth embodiment, the same parts are given the same reference numerals and the explanation will be omitted.

The storage device 400 includes a container 401 in which an object to be measured is stored, a Peltier element 402 attached to the bottom of the container 401, a temperature sensor 403 that detects the temperature of the container 401, and a temperature sensor 403 that detects the temperature based on the detection result of the temperature sensor 403. It has a control section 404 that controls the Peltier element 402. The container 401 has an open top surface, and the object to be measured S is accommodated through this opening. Further, the Peltier element 402 is attached to the container 401 so that the heat generating side thereof is in contact with the bottom surface of the container 401.

In the spectroscopic measurement unit described above, a liquid measurement object S, for example, is stored in a container 401, and the container 401 is heated to a predetermined temperature using a Peltier element 402. As a result, the volatile components (moisture) contained in the measurement target S in the container 401 are evaporated, and the non-volatile components remain in the container 401. In this state, the opening of the container 401 and the opening of the casing 301 of the spectrometer 300 are butted against each other. Then, the radiant heat emitted from the non-volatile components remaining in the container 401 enters the casing 301 through the opening of the container 401 and the opening of the casing 301. As a result, as explained in the fourth embodiment, the spectral characteristics of the radiation light are determined.

In the above embodiments, the present invention is applied to a spectrometer, but the present invention also applies to infrared thermography for measuring the heat distribution of a measurement object, and radiant light emitted from the measurement object. It can also be applied to a radiant light intensity measurement device that measures the intensity of light.
In addition, in the above embodiment, a thermally conductive sheet or a heat insulating sheet is provided inside the housing, but when a cooling means for cooling the housing or the radiation light detector is provided, a thermally conductive sheet and a heat insulating sheet are used. may be omitted.

1, 100, 200, 200A, 300, 300A... Spectrometer 10, 101, 201, 301... Housing 202... Window section 250... Ultrasonic heating device 251... Ultrasonic vibrator 255, 256... Ultrasonic vibration setting section 290...insulating sheet 40, 220, 340...detector 70...inlet 90, 390...graphite sheet 95, 96, 395, 402...Bertier element 391...contact part

Claims (10)

a casing having a window;
a radiant light detector arranged in the housing that detects radiant light from the measurement target that enters through the window;
A cooling means for cooling an optical path of radiant light from the window to the radiant light detector and the radiant light detector to a predetermined temperature lower than the temperature of the measurement object,
A radiation light detection device that detects radiation light from the object to be measured in a state where the temperature of the optical path of the radiation light and the radiation light detector is lower than the temperature of the object to be measured. The radiation light detection device according to claim 1,
A radiation light detection device, wherein the cooling means includes a thermally conductive sheet provided in the housing so as to surround the optical path. The radiation light detection device according to claim 2,
A radiant light detection device, wherein the thermally conductive sheet has a contact portion that is brought into contact with the radiant light detector or the object to be measured. The radiation light detection device according to claim 1,
A radiation light detection device, wherein the cooling means cools the casing. The radiation light detection device according to claim 1,
The cooling means further includes:
an optical path temperature detector that detects the temperature within the optical path;
an optical path temperature setting section for setting the temperature within the optical path;
A radiant light detection device, comprising: a control section that controls the cooling means so that the temperature reaches the temperature set by the optical path temperature setting section. The radiation light detection device according to claim 1, further comprising:
A radiation light detection device equipped with a heating means for heating an object to be measured. The radiation light detection device according to claim 6,
A radiation light detection device, wherein the heating means includes an ultrasonic transducer provided in the housing so as to surround the window. The radiation light detection device according to claim 7,
A radiation light detection device, wherein the heating means further includes an ultrasonic vibration setting section that sets the frequency and/or amplitude of ultrasonic vibrations emitted by the ultrasonic vibrator. The radiation light detection device according to any one of claims 6 to 8, further comprising:
an object temperature detector that detects the temperature of the measurement object;
an object temperature setting unit for setting the temperature of the measurement object;
A radiation light detection device, comprising: a control section that controls the heating means so that the temperature reaches the temperature set by the object temperature setting section. The radiation light detection device according to claim 1,
The radiation light detector has a light receiving surface and is configured to detect the intensity distribution of light on the light receiving surface,
a collimating unit disposed on the optical path between the window and the radiation light detector, which converts the radiation light from the measurement point provided on the measurement object into a parallel beam; a collimating unit that converts the parallel beam into a first beam; and a phase shifter that divides the beam into a second beam and emits the beam while imparting an optical path length difference between the first beam and the second beam, the radiation beam so that the first beam and the second beam overlap each other at least in part; an interference optical system that causes the light to enter the light receiving surface of the photodetector;
a processing unit that obtains an interferogram of the measurement point based on the light intensity distribution of the light receiving surface in a portion where the first light beam and the second light beam overlap, and obtains a spectrum by Fourier transforming the interferogram; A radiation light detection device having and .

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